Spalding NBA Slam Jam Over-The-Door Mini Basketball Hoop for $25.00. Shipping is free on orders over $35. If needed, use this Filler Tool to pad the order for free shipping. Here is a screenshot for reference. The NBA Slam Jam is made at a 1/4″ scale replica of actual NBA game backboard, keeping the proportions the same as the professional level backboards, and the design features a color NBA Logoman.